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Progress Towards Understanding Quarkonia at PHENIX Mike Leitch – PHENIX/LANL– leitch@bnl

Progress Towards Understanding Quarkonia at PHENIX Mike Leitch – PHENIX/LANL– leitch@bnl.gov WWND 08 – South Padre Island, TX – 5-12 April 2008. How are quarkonia produced? What CNM effects are important? How does the sQGP effect quarkonia? What are the CNM effects in AA collisions?

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Progress Towards Understanding Quarkonia at PHENIX Mike Leitch – PHENIX/LANL– leitch@bnl

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  1. Progress Towards Understanding Quarkonia at PHENIX Mike Leitch – PHENIX/LANL– leitch@bnl.gov WWND 08 – South Padre Island, TX – 5-12 April 2008 • How are quarkonia produced? • What CNM effects are important? • How does the sQGP effect quarkonia? • What are the CNM effects in AA collisions? • Transverse Momentum Broadening • Heavier Quarkonia • Detector Upgrades & Luminosity for the future Mike Leitch - PHENIX/LANL

  2. How are Quarkonia Produced? • Gluon fusion dominates • Color singlet or octet cc: absolute cross section and polarization? Difficult to get both correct! • Configuration of cc is important for pA cold nuclear matter effects • Complications due to substantial feed-down from higher mass resonances (’, c ) PRL 91, 211801 (2003) E866 800 GeV xF = x1 – x2 • Polarization • NRQCD models predict large transverse polarization (>0) at large pT • but E866 & CDF show small or longitudinal (<0) polarization • recently, Haberzettl, Lansberg, PRL 100, 032006 (2008) - looks better BR•tot = 178 ± 3 ± 53 ± 18 nb Cross Sections PHENIX Run5 p+p data (PRL 98:232002,2007) begins to constrain shape of cross section vs rapidity & pT, but higher accuracy needed Mike Leitch - PHENIX/LANL

  3. R. Vogt, NRQCD calculations Nucl. Phys. A700(2002) 539 C singlet All J/ψ’s direct J/ψ octet Ψ’ HERA-B xF range 920 GeV = mc-mJ/y How are Quarkonia Produced? Feeddown to J/ψ J/ψ from ψ’ 8.6 ± 2.5% J/ψ from c < 42% (90% CL) Nuclear dependence of (parent) resonance, e.g. C is probably different than that of the J/ψ Also measure of B  J/ψ - 4 +– 32 % see Y. Morino talk on Wed Mike Leitch - PHENIX/LANL

  4. Absorption (or dissociation) of into two D mesons by nucleus or co-movers (the latter most important in AA collisions where co-movers more copious) low x Energy loss of incident gluon shifts effective xF and produces nuclear suppression which increases with xF high x R(A/D) R=1 xF What CNM effects are important? (CNM = Cold Nuclear Matter) Traditional shadowing from fits to DIS or from coherenece models 10 GeV 5 GeV Q = 2 GeV Gluon saturation from non-linear gluon interactions for the high density at small x; amplified in a nucleus. Mike Leitch - PHENIX/LANL

  5. What CNM effects are important? (CNM = Cold Nuclear Matter) J/ for different s collisions Small x (shadowing region) 200 GeV PRC 77,024912(2008) 19 GeV 39 GeV = X1 – X2 (x2 is x in the nucleus) • New Analysis of Run3 data consistent with EKS shadowing & absorption - clear need for new dAu data • latest shadowing (EPS08)  2x stronger (Brahms forw. data in fit) • Not universal vs x2 as expected for shadowing, but closer to scaling with xF, why? • initial-state gluon energy loss? • gluon saturation? • Sudakov suppression (energy conservation)? Mike Leitch - PHENIX/LANL

  6. What CNM effects are important? Latest PHENIX J/’s from Run8 200 GeV d+Au 4,369 J/  ee (~6,000 from all data) Expected improvement in CNM constraints (red) compared to Run3 (blue) 59 nb-1 simulation 63 nb-1 expected accuracy 57,030 J/   (~73,000 from all data) Mike Leitch - PHENIX/LANL

  7. How does the QGP affect Quarkonia? Debye screening predicted to destroy J/ψ’s in a QGP with other states “melting” at different temperatures due to different sizes or binding energies. • PHENIX AuAu data shows suppression at mid-rapidity about the same as seen at the SPS at lower energy, but stronger suppression at forward rapidity. • Forward/Mid RAA ratio looks flat above Npart = 100 • Several alternative scenarios can be considered: • Cold nuclear matter (CNM) effects • in any case are always present • Sequential suppression • screening only of C & ’- removing their feed-down contrib. to J/ • Regeneration models • give enhancement that compensates for screening Mike Leitch - PHENIX/LANL

  8. How does the QGP affect Quarkonia? CNM Effects CNM effects (EKS shadowing & dissocation – see earlier dAu slide) give large fraction of observed AuAu suppression, especially at mid-rapidity • Normal CNM descriptions (blue) give similar (or even smaller) suppression at mid vs forward rapidity • but if peaking in “anti-shadowing” region were flat instead (red dashed) then one would get larger suppression for forward rapidity as has been observed in AuAu data • this could come from gluon saturation or from a shadowing prescription that has no anti-shadowing In any case more accurate dAu data is sorely needed Mike Leitch - PHENIX/LANL

  9. SPS overall syst (guess) ~17% 0 = 1 fm/c used here PHENIX overall syst ~12% & ~7% How does the QGP affect Quarkonia? Sequential Screening and Gluon Saturation Survival Probability wrt CNM • Recent lattice calculations suggest J/ψ not screened after all. • suppression then comes only via feed-down from screened C & ’ • the situation could be the same at lower energies (SPS) as for RHIC mid-rapidity • and the stronger suppression at forward rapidity at RHIC could come from gluon saturation (previous slide) • Issues: • Is suppression stronger than can come from C & ’ alone? • Can this picture explain saturation of the forward/mid RAA ratio? Mike Leitch - PHENIX/LANL

  10. Grandchamp, Rapp, Brown PRL 92, 212301 (2004) nucl-ex/0611020 How does the QGP affect Quarkonia? Regeneration • Regeneration models give enhancement that compensates for screening • larger gluon density at RHIC expected to give stronger suppression than SPS • but larger charm production at RHIC gives larger regeneration • very sensitive to poorly known open-charm cross sections • forward rapidity lower than mid due to smaller open-charm density there • expect inherited flow from open charm • regeneration much stronger at the LHC! • Issues: • need to know what happens to C & ’ & measure J/ flow • flat forward/mid RAA seems inconsistent with increasing regeneration & screening for more central collisions Mike Leitch - PHENIX/LANL

  11. How does the QGP affect Quarkonia? J/ flow • J/ψ’s from regeneration should inherit the large charm-quark elliptic flow • First J/ψ flow measurement by PHENIX: • v2 = –10 ± 10 ± 2 ± 3 % Run-4 PRELIMINARY Run-7 minimum-bias Mike Leitch - PHENIX/LANL

  12. Transverse Momentum Broadening Another Cold Nuclear Matter Effect PRC 77, 024912 (2008) PHENIX 200 GeV dAu shows some pT broadening, but may be flatter than at lower energy (s=39 GeV in E866/NuSea) High x2 ~ 0.09 Initial-state gluon multiple scattering causes pT broadening (or Cronin effect) Low x2 ~ 0.003 Also can be looked at in terms of <pT2> Mike Leitch - PHENIX/LANL

  13. Transverse Momentum Broadening in AA Collisions • Relatively flat with centrality - slight increase at forward rapidity • CNM effects should broaden pT • initial-state mult. scatt. for both gluons • Regeneration should narrow pT • square of small-pT peaked open-charm cross section • Other effects in the presence of a QGP? • early escape at high- pT? • “hot wind” suppression at high-pT (5-9 GeV/c)? <pT2> for AuAu arXiv:0801.0220 Mike Leitch - PHENIX/LANL

  14. =10.24/8 4145 J/ give ~80 c candidates Feeddown to J/ <42% (90% CL) ’e+e- p+p 200GeV, Run-6 PHENIX Run 5 200GeV p+p Other pieces of the J/ puzzle: the c, ’,  ~27 cnts 1st Upsilons at RHIC QM05 Feeddown fraction to J/ 0.086 ± 0.025 Mike Leitch - PHENIX/LANL

  15. FVTX Si Endcaps Nose Cone Calorimeter VTX Si Barrel PHENIX Upgrades • Vertex detectors (VTX,FVTX) & forward calorimeter (NCC) will give: • ’ msmt with reduced combinatoric background + sharper mass resolution • C msmt with photon in NCC • precise open-heavy measurements to constrain regeneration picture 1S • FVTX: • 4x less ,K decays • M: 170100 MeV 2S J/ C ’ Mike Leitch - PHENIX/LANL

  16. RHIC Luminosity Advances will Enable Access to Heavier Quarkonia 100,000 J/   and ~250    per year at highest RHIC luminosities max min J/ &    max #J/ # x100 min Mike Leitch - PHENIX/LANL

  17. Progress Towards Understanding Quarkonia at PHENIX - Summary Better CNM baseline coming from Run8! forward/mid rapidity super-ratio saturates @~0.6 Sequential screening & (forward) gluon saturation? flow from regeneration is difficult to see PHENIX overall syst ~12% & ~7% Mike Leitch - PHENIX/LANL

  18. Backup Slide(s) Mike Leitch - PHENIX/LANL

  19. EPS08 (Strong) Shadowing Eskola, Paukkunen, Salgado, hep-ph 0802.0139v1 Fit includes RHIC (Brahms) forward hadron data (as well as the usual DIS and DY data) Mike Leitch - PHENIX/LANL

  20. Another shadowing scheme? Shadowing from Schwimmer multiple scattering : + E-p conservation + regeneration Shadowing effect: NDSG: (y=0) < (y=1.7) EKS: (y=0) ≈ (y=1.7) Schwimmer: (y=0) > (y=1.7) Capella et al, arXiv:0712.4331 Mike Leitch - PHENIX/LANL

  21. Tuchin & Kharzeev… Gluon saturation (CGC) can give xF scaling of pA J/ suppression at various energies Mike Leitch - PHENIX/LANL

  22. RAuAu vs RCuCu CuCu provides more accurate RAA at smaller Npart, but within errors confirms the trends seen in AuAu in that region RAA(y~1.7)/RAA(y~0) PHENIX, arXiv:0801.0220 Mike Leitch - PHENIX/LANL

  23. New results from Run7 AuAu data Preliminary analysis of new Run7 AuAu forward rapidity (dimuon) J/ data (black points) is consistent with published results (blue points) from Run4 Mike Leitch - PHENIX/LANL

  24. Recombination of charm quarks could cancel the Cronin and leakage effects. Need more statistics to draw a conclusion. L. Yan, P. Zhuang and N. Xu, Phys. Rev. Lett. 97, 232301 (2006) X. Zhao and R. Rapp, arXiv:0812.2407 [hep-ph] arXiv:0801.0220 [nucl-ex] <pT2> vs Npart without recombination with recombination Mike Leitch - PHENIX/LANL

  25. bottom fraction in non-photonic electron • The result is consistent with FONLL

  26. The J/ Puzzle ~40% feedown from C, ’ (uncertain fraction) configuration of ccbar state • PHENIX J/ Suppression: • like SPS at mid-rapidity • stronger at forward rapidity with forw/mid ~0.6 saturation • <pT2> centrality indep. absorption d+Au constraint? Data – SPS, PHENIX, STAR, LHC… Need high statistical & systematic accuracy shadowing or coherence CNM CGC - less charm at forward rapidity Regeneration & destruction less suppression at mid-rapidity narrowing of pT & y J/ flow comovers more mid-rapidity suppression Sequential screening C, ’ 1st, J/ later Regeneration (in medium?) lattice & dynamical screening J/ not destroyed? large gluon density destroys J/’s large charm cross section Charm dE/dx & flow Mike Leitch - PHENIX/LANL

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